Mobile robotic vacuum cleaner with a obstacle sensing function

ABSTRACT

A mobile robotic vacuum cleaner with obstacle sensing function is disclosed to include a machine body, a first running wheel and a second running wheel mounted in the machine body at two opposite sides in such a position that the extension line of the wheel shafts of the first and second running wheels divides the machine body into a front part and a rear part, and one or multiple rear obstacle sensors mounted in the rear part of the machine body to detect rear obstacles, avoiding the mobile robotic vacuum cleaner from falling down the stairs or dropping in a hole during its backward movement.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to mobile robotic vacuum cleanertechnology and more specifically, to a mobile robotic vacuum cleanerwith obstacle sensing function.

2. Description of the Related Art

A conventional mobile robotic vacuum cleaner is known comprising amachine body, a directional wheel mounted in the front part of themachine body, a left running wheel and a right running wheelrespectively mounted in the machine body at rear-left and rear-rightsides relative to the directional wheel, and a plurality of obstaclesensors spaced around the front side of the machine body. Duringoperation of the aforesaid conventional mobile robotic vacuum cleaner,the direction wheel controls the steering direction, and the left andright running wheels are controlled to move the machine body forwards orbackwards. During forward movement of the mobile robotic vacuum cleaner,the obstacle sensors detect any obstacle in the forward path, forexample, elevation difference. When an obstacle is sensed, one of theleft and right running wheels will be kept immovable, and the other ofthe left and right running wheels will be rotated backwards to changethe steering direction of the mobile robotic vacuum cleaner and to avoidthe obstacle. However, the aforesaid conventional mobile robotic vacuumcleaner does not have any sensor means to detect backward obstacles.Thus, when the mobile robotic vacuum cleaner moves backwards to avoid afront obstacle, it cannot detect any rear obstacle and may fall down thestairs or drop in a hole.

SUMMARY OF THE INVENTION

The present invention has been accomplished under the circumstances inview. It is the main object of the present invention to provide a mobilerobotic vacuum cleaner with obstacle sensing function, which detects anyrear obstacles when moving backwards.

To achieve these and other objects of the present invention, a mobilerobotic vacuum cleaner with obstacle sensing function comprises amachine body, a first running wheel and a second running wheel mountedin the machine body at two opposite sides in such a position that theextension line of the wheel shafts of the first and second runningwheels divides the machine body into a front part and a rear part, frontobstacle sensors mounted in the front part of the machine body andadapted for sensing front obstacles, and at least one rear obstaclesensor mounted in the rear part of the machine body and adapted forsensing rear obstacles. Subject to the functioning of the at least onerear obstacle sensor, the mobile robotic vacuum cleaner will not falldown the stairs or drop in a hole when moving backwards.

Further, the at least one rear obstacle sensor can be mounted in theperiphery of the rear part of the machine body at a rear side relativeto the first running wheel. Alternatively, the at least one rearobstacle sensor can be mounted in the periphery of the rear part of themachine body at a rear side relative to the second running wheel.Alternatively, the at least one rear obstacle sensor can include tworear obstacle sensors mounted in the periphery of the rear part of themachine body and respectively disposed at a rear side relative to thefirst running wheel and the second running wheel.

Other and further advantages and features of the present invention willbe fully understood by reference to the following specification inconjunction with the accompanying drawings, in which life referencesigns denote like elements of structure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an oblique top elevation of a mobile robotic vacuum cleanerhaving obstacle sensing function in accordance with the presentinvention.

FIG. 2 is an oblique bottom elevation of the mobile robotic vacuumcleaner having obstacle sensing function in accordance with the presentinvention.

FIG. 3 is schematic bottom view of the mobile robotic vacuum cleanerhaving obstacle sensing function in accordance with the presentinvention, illustrating the arrangement of the obstacle sensors in therear part of the machine body.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1-3, a mobile robotic vacuum cleaner 10 in accordancewith the present invention is shown comprising a machine body 20, afirst running wheel 30, a second running wheel 40 and two obstaclesensors 50.

The machine body 20 is shaped like a flat cylinder movable on a surface,for example, the floor. The machine body 20 is formed of a plastichousing, a power drive and a control circuit. The power drive and thecontrol circuit are housed inside the plastic housing. Because the powerdrive and the control circuit are of the known art and not within thescope of the claims of the present invention, no further detaileddescription in this regard is necessary.

The first running wheel 30 and the second running wheel 40 aresymmetrically mounted in the machine body 20. Further, the extensionline L of the wheel shafts of the first and second running wheels 30,40divides the machine body 20 into a front part 21 and a rear part 23. Themachine body 20 is equipped with a directional wheel 211 in the frontpart 21. The directional wheel 211 is rotatable through 360-degrees tocontrol the steering direction of the machine body 20. Further, threefront obstacle sensors 213 are equiangularly spaced along the peripheryof the front part 21 for sensing obstacles in the front side of themachine body 20. The directional wheel 211 and the front obstaclesensors 213 are of the known art, no further detailed description inthis regard is necessary.

The main feature of the present invention is the arrangement of the twoobstacle sensors 50. In this embodiment, these two obstacle sensors 50function in the same manner as the aforesaid front obstacle sensors 213,i.e., using a light emitter to emit light toward the surface in theforward path and a light receiver to receive reflected light fordetermining the surface status in the forward path. With respect to theprinciple of work of these obstacle sensors 50, please refer to U.S.Pat. No. 7,411,744. One of these two obstacle sensors 50, as shown inFIG. 2, is installed in the periphery of the rear part 23 of the machinebody 20 at a rear-right side relative to the second running wheel 40 andadjacent to the second running wheel 40. The other end of these twoobstacle sensors 50 is installed in the periphery of the rear part 23 ofthe machine body 20 at a rear-right side relative to the first runningwheel 30 and adjacent to the first running wheel 30. Thus, the obstaclesensors 50 detect obstacles in the rear side when the mobile roboticvacuum cleaner 10 moves backwards to avoid a rear obstacle.

Further, the number of the obstacle sensors 50 is not limited to 2,i.e., the number of the obstacle sensors 50 may be changed subject toactual requirements. For example, only one obstacle sensor 50 isinstalled in one lateral side of the rear part 23 of the mobile roboticvacuum cleaner 10 at a rear-right side relative to the first runningwheel 30 or rear-right side relative to the second running wheel 40 andadjacent to the first running wheel 30 or second running wheel 40.

When the mobile robotic vacuum cleaner 10 is moving forward duringoperation, the front obstacle sensors 213 detect any obstacle, forexample, elevation different in the forward path in front of the machinebody 20. When an obstacle is sensed, one of the first and second runningwheels 30,40 will be kept immovable, and the other of the left and rightrunning wheels 30,40 will be rotated backwards to change the steeringdirection of the mobile robotic vacuum cleaner 10 and to avoid theobstacle. During a backward movement of the mobile robotic vacuumcleaner 10, the obstacle sensors 50 detect any rear obstacles. Subjectto the detection of the obstacle sensors 50, the mobile robotic vacuumcleaner 10 is controlled to keep moving backwards or to change thesteering direction.

In conclusion, the mobile robotic vacuum cleaner with obstacle sensingfunction has sensors installed in the rear part of the machine bodythereof to detect rear obstacles, avoiding the mobile robotic vacuumcleaner from falling down the stairs or dropping in a hole during itsbackward movement.

Although a particular embodiment of the invention has been described indetail for purposes of illustration, various modifications andenhancements may be made without departing from the spirit and scope ofthe invention. Accordingly, the invention is not to be limited except asby the appended claims.

1. A mobile robotic vacuum cleaner, comprising: a machine body; a firstrunning wheel and a second running wheel mounted in said machine body attwo opposite sides, said first running wheel and said second runningwheel each having a wheel shaft, the extension line of the wheel shaftsof said first running wheel and said second running wheel dividing saidmachine body into a front part and a rear part; at least one frontobstacle sensor mounted in said front part of said machine body andadapted for sensing the presence of an obstacle in front of said machinebody; wherein the mobile robotic vacuum cleaner further comprises atleast one rear obstacle sensor mounted in said rear part of said machinebody and adapted for sensing the presence of an obstacle behind saidmachine body.
 2. The mobile robotic vacuum cleaner as claimed in claim1, wherein said at least one rear obstacle sensor is mounted in theperiphery of said rear part of said machine body at a rear side relativeto said first running wheel.
 3. The mobile robotic vacuum cleaner asclaimed in claim 1, wherein said at least one rear obstacle sensor ismounted in the periphery of said rear part of said machine body at arear side relative to said second running wheel.
 4. The mobile roboticvacuum cleaner as claimed in claim 1, wherein said at least one rearobstacle sensor comprises two rear obstacle sensors mounted in theperiphery of said rear part of said machine body and respectivelydisposed at a rear side relative to said first running wheel and saidsecond running wheel.